1. Field of the Invention
The present invention relates to an optical information recording medium capable of recording and reproducing information on an optical disk or card or the like by using a focused laser beam.
2. Description of the Prior Art
Conventionally, as organic recording materials for use with a semiconductor laser, which can be used in practice, those for use with a laser beam having a wavelength of 750 to 850 nm are commonly known. Representative examples of such recording materials comprise a substrate and a thin film layer of a polymethine dye such as a cyanine dye, a phthalocyanine dye, a naphthoquinone dye, a naphthalocyanine dye, or a squarylium dye, formed on the substrate, as described in "Organic Recording Materials for Optical Disks" by M. Abe, one of the inventors of the present invention, compiled by the Japanese Research Association for Organic Electronics Materials, published by Bunshin Publishing Company (1989). However, these dyes lack in the light absorption or light reflection properties in the short wavelength region of 400 to 500 nm, so that there is a limitation in utilizing these dyes for high density recording.